1. Field of the Invention
This invention relates, generally, to bailers. More particularly, it relates to a bailer having multiple check valves that reduce leakage of sample fluid from the bailer.
2. Description of the Prior Art
Bailers are used to sample liquid fluid from wells or other bodies of liquid fluid. The sample fluid retrieved using a bailer is tested and analyzed, usually by governmental authorities or their contractors, for impurities and contaminants. A typical bailer has a slender tubular-shaped main body and a check valve at the bottom end thereof. As an operator lowers the bailer into a liquid fluid using a cable or line attached to a top end of the bailer, the check valve opens and fluid enters the hollow interior of the bailer. The air displaced by the fluid exits the bailer from the open upper end thereof. The air flowing out of the top of the bailer prevents liquid fluid from entering the bailer through said open top.
When a filled bailer is removed from the body of liquid fluid, the check valve closes and secures the liquid sample within the bailer. The liquid sample is then distributed from the bailer to individual test containers for a battery of tests.
One of the problems confronting the bailer industry is leakage from a bailer via the check valve after a sample has been drawn. Leakage is undesirable for two primary reasons. First, the sample fluid captured within the bailer may be contain acids or other harmful constituents that may cause irritation if allowed to leak onto the skin of the operator taking the sample after the bailer is retrieved. Secondly, bailers are sized to hold a predetermined volume of liquid fluid that correlates with a particular testing protocol. Accordingly, excessive leakage of fluid from the bailer may necessitate a repeated sampling of the well or other body of fluid to accumulate the required sampling volume.
Leakage problems are compounded when the liquid fluid being sampled contains particulate matter such as sand. The sand or other particulate matter gets between the check valve seat and the check valve ball and prevents the ball from sealing the valve seat.
U.S. Pat. No. 5,507,194 to Scavuzzo et al. (hereinafter xe2x80x9cScavuzzoxe2x80x9d) describes a disposable bailer having an inlet means and an integrated check valve that includes a check ball that rests in a check seat at the lowermost end of the bailer as in many other prior art bailers. Scavuzzo discloses an improved design of the check valve whereby premature unseating of the check ball is prevented during emptying of the fluid sample into analysis containers. Specifically, the check valve is designed to not open until the bailer is near a horizontal position and mostly empty. An upper or outlet check valve means is designed to close when the bailer begins the ascent from the fluid body. Scavuzzo does not provide an improved means that reduces leakage of the fluid sample from the lower end of the bailer.
U.S. Pat. No. 4,050,315 to Markfelt describes a bailer that includes an upper spherical valve member activated when an operator imparts a sharp jerk on the lowering cable when the sampler has reached a desired depth. Once activated, the valve member lifts from an upper valve seat and allows fluid to fill the bailer with fluid from a desired depth. As the bailer fills, a lower floating ball contained within the body of the bailer rises to seat in a lower valve seat. The Markfelt invention thus enables the collection of a sample of liquid fluid from a predetermined depth, but the problem of leakage at the lowermost end of the bailer is not addressed.
Accordingly, there remains a need for a bailer design that does not leak.
However, in view of the prior art, considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the needed bailer could be provided.
The long-standing but heretofore unfulfilled need for a bailer that does not leak is now provided by a new, useful, and nonobvious bailer. The novel bailer includes an elongate, tubular main body having a hollow interior, an upper end and a lower end. A primary check valve is slidingly received within the hollow interior at the lower end and at least one auxiliary check valve is slidingly received within the hollow interior in longitudinally spaced relation to the primary check valve. A barrier means is slidingly received within the hollow interior in longitudinally spaced relation to the at least one auxiliary check valve. The at least one auxiliary check valve is disposed between the primary check valve and the barrier means. The primary check valve and the at least one auxiliary check valve admit liquid fluid into the hollow interior of the bailer when the bailer is immersed within a body of liquid fluid. The primary and auxiliary check valves work in combination with one another to inhibit leakage of liquid fluid from the hollow interior.
At least some particulate matter in the liquid fluid contained within the hollow interior is collected in an annular trough formed at the lowermost end of the bailer. Additional particulate matter is collected by one or more pockets formed in the auxiliary valve assembly.
It is therefore understood that the primary object of this invention is to provide a bailer that doesn""t leak.
A closely related is to provide a non-leaking bailer that is simple in construction, inexpensive to manufacture, reliable, and easy to assemble.
Another very important object is to provide a bailer that can be used effectively even when a liquid fluid being sampled contains particulate matter.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.